What version of MediaLab are you using? I ask because more recent versions of MediaLab no long have the "Use Enhanced Video" option because it was redundant with changes made to the software to address issues with playing video files.
Could you also describe in more detail what kind of problems you are having with the sound? Is it not playing at all? Is it playing but garbled? Also, uploading a copy of your MediaLab .que or .exp file that you are using to play the video file through MediaLab could be helpful for me to give it a look.
Jason Reed
Empirisoft Software Support Specialist